CEPHALOPODA OF THE HAWAIIAN ISLANDS. 



339 



singly, together broadly sagittate; posterior outlines nearly straight, anterior ones arcuate and lobed 

 at the inner margin; total length a little less than two-fifths that of the mantle. 



Head large, a little broader than the body; flattened above and below; bounded posteriorly by 

 raised thickened fleshy ridge, which is continuous with the three ear-like folds behind the eye composing 



the so-called olfactory crest. Eyes large, the large lid apertures 

 with a small indented sinus in front. 



Arms moderate, stout, squarish, little attenuate, their aver- 

 age length about half that of the mantle; order of length in 

 general 2, 3, 1, 4, or in younger specimens 2, 3, 1=4; not 

 webbed at the base, but all strongly keeled along the outer 

 angle, and with a narrow trabeculated membrane bordering the 

 margins of the sucker-bearing area; the latter attaining its max- 

 imum along the ventral margins of the third arms, but scarcely 

 developed on the ventral pair. Suckers large, distant; regu- 

 larly alternating in two series so closely appressed together that 

 they have rather the appearance of a single zigzag row; those 

 of the dorsal arms distinctly smaller than the others; those of 

 the lateral pairs largest, some of those near the middle of the 

 arm attaining a diameter 

 almost as great as that of 

 the arm itself; on the arms 

 of the second pair only 

 about 36 to 40 suckers in 

 all can be readily counted. 

 Horny rings of the larger 

 suckers with 19 to 2 1 teeth, 

 the upper median tooth 

 conspicuously the largest 

 and more regularly conical 

 in shape than the others; 

 those of the lower margin 

 blunt and much reduced 

 (obsolete in the smaller 



suckers), the remainder acutely pointed; an occasional very 

 minute denticle may be interpolated among the teeth of the 

 upper margin. 



Tentacles stout, of moderate length, some two-thirds or 

 more as long as the mantle; outer margin carinate; club 

 slightly expanded, large, the sucker bearing area including 64 

 to 70 per cent of the total length of the tentacle. Suckers in 

 four rows; all of small size at the extremity, the ventral row 

 largest, thence very regularly decreasing in size dorsally ; at the 

 middle of the club the dorsal and ventral series about equal , 

 but still very small and widely spaced, the suckers of the 

 two median rows immensely larger (and therefore more 

 crowded) and basin shaped, but proximally again showing 

 a diminution in size; at the base of the club the central rows 

 terminate, the marginal series continuing past them for a short 

 distance down the stalk. The horny rings of the large median suckers are toothed all round, the 

 13 to 16 acutely-pointed curved teeth occurring in regular alternation with an equal number of wide, low, 

 very thin arcuate plates; upper median tooth much larger and more pointed than the others, very much 

 as already noted in the case of the suckers of the sessile arms. The small marginal suckers are much 



W: 



I? 



w 



f ■ 



3 



Fig. 39. — Ommaslrephes hawaiiensis [242] 

 outline drawing of funnel organ, nat- 

 ural size. 



FiG. 38. — Ommaslrephes hawaiiensis, ventral 

 view of type [243]. X J4. Drawn by R. L. 

 Hudson. 



